GLP-1 Analogue: What It Is and Which Are Used for Weight Loss (October 2026)

01 · The core answer

What does GLP-1 analogue mean?

A GLP-1 analogue is a medicine designed to resemble glucagon-like peptide-1, a hormone your gut releases after eating. The medicine binds to the same receptor, but is built to work for far longer than the natural hormone, which is why a weekly injection can be enough. You will also see the terms GLP-1 receptor agonist, incretin mimetic and, in American spelling, 'GLP-1 analog'. In everyday use they mean much the same thing.

In practice, the effect that matters for weight loss is on appetite and digestion. Together, tirzepatide's actions help regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin.¹ Most people feel fuller sooner and less hungry between meals, which supports a reduced-calorie diet.¹

02 · Which medicines

Which UK medicines are GLP-1 analogues?

Several UK medicines act on the GLP-1 pathway, but they differ in licence, schedule and how they work.

Foundayo is described in the trial literature as an oral small-molecule GLP-1 receptor agonist, so it acts on the same pathway without being a copy of the hormone itself.²³ Wegovy is a once-weekly injection, while liraglutide is a daily one.¹⁸

03 · Your next step

Is this relevant to me, and what next?

It is relevant if you are an adult considering medical weight management. Mounjaro is licensed for weight management in adults, and a prescriber decides whether it suits your health, your other medicines and your routine. Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber, and it is used alongside a reduced-calorie diet and increased physical activity.¹

If you want to see what treatment looks like in practice, our Mounjaro pen page has current prices and the free consultation, and our weight loss clinic page explains the wider service. Your first 2.5mg pen costs £129.99 with code FIRST40 (standard price £169.99).

Related guides: Agonisti glp 1 and Ozempil glp-1.

04 · Tirzepatide: more than an analogue

Is tirzepatide a GLP-1 analogue?

Tirzepatide acts on the GLP-1 receptor, but it is better described as a dual agonist. Tirzepatide is the first treatment of its kind to activate two natural gut-hormone receptors at once: GIP and GLP-1.¹ That dual action is what distinguishes Mounjaro from single-action GLP-1 medicines such as semaglutide.¹

Does the extra receptor matter in trials? SURMOUNT-5 is the first large head-to-head trial of tirzepatide and semaglutide. In it, adults on tirzepatide lost on average 20.2% of body weight over 72 weeks versus 13.7% on semaglutide 2.4mg (Wegovy).¹⁵ Both are effective, licensed treatments, and which suits you depends on your health profile, tolerance and prescriber advice, not the headline number alone.¹⁵

In SURMOUNT-1, people on tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone.² These are trial averages, and individual results vary.²

05 · Semaglutide, Ozempic and Wegovy

Is Ozempic a GLP-1 analogue?

Yes, Ozempic contains semaglutide, a GLP-1 analogue, but its UK licence is for type 2 diabetes. It is not a UK weight-loss medicine, and prescribing it privately for weight loss is off-label.¹¹ The licensed weight-management options are Mounjaro (tirzepatide) and Wegovy (semaglutide 2.4mg). A regulated UK pharmacy will not supply Ozempic for weight loss.

In STEP 1, adults on semaglutide 2.4mg (Wegovy) lost on average 14.9% of body weight over 68 weeks, compared with 2.4% on placebo.⁹

06 · GLP-1 tablets

Is there a GLP-1 analogue tablet?

Yes, two GLP-1 tablets are now licensed in the UK for weight management, but there is no tablet form of Mounjaro, as tirzepatide is injection-only in the UK.²⁰ Both tablets are prescription-only and have their own dosing, eligibility checks and trial results.

Wegovy tablets contain semaglutide, the same active ingredient as the Wegovy injection, taken as one tablet once a day.²⁰ The tablet must be taken on an empty stomach after fasting for at least 8 hours, swallowed whole with a sip of water (up to half a glass, about 120ml), and you then wait at least 30 minutes before eating, drinking or taking other tablets.²⁰ In the OASIS 4 trial, adults taking semaglutide 25mg tablets for 64 weeks lost on average 13.6% of their body weight, compared with 2.2% on placebo.²²

Foundayo contains orforglipron, a once-daily GLP-1 tablet made by Eli Lilly. Unlike Wegovy tablets it can be taken at any time of day, with or without food and without water restrictions.²¹ In the ATTAIN-1 trial of 3,127 adults without type 2 diabetes, people taking the highest dose of orforglipron for 72 weeks lost on average 12.4% of their body weight, compared with 0.9% on placebo.²³

No trial has compared Mounjaro directly with either tablet, so results from separate trials, with different people, durations and doses, should not be set against each other as if they were head to head.¹⁵ The practical differences matter as much as the averages: a strict morning routine, no food rules, or one injection a week.

07 · Side effects and safety

Side effects across GLP-1 medicines

Digestive side effects are the most common problem across the class. For Wegovy tablets, the most common are nausea, vomiting, diarrhoea, constipation, indigestion and stomach pain, along with headache and tiredness; gallstones and hair loss are listed as common.²²

In STEP 1, gastrointestinal side effects were reported by 74.2% of people on semaglutide 2.4mg, compared with 47.9% on placebo, and 7.0% stopped treatment because of side effects, compared with 3.1% on placebo.⁹ A prescriber can help with tolerability, and you can report any suspected side effect through the Yellow Card scheme.¹⁹

Never run two GLP-1 medicines together. Mounjaro must not be combined with other GLP-1 medicines, unlicensed 'research' peptides (such as retatrutide, which has no UK licence), or compounded copies.¹ These combinations have no safety data and no regulated supply chain. If something promises faster results outside a licensed pathway, that is the warning sign.

08 · Natural alternatives

'Natural GLP-1' and 'poor man's Ozempic'

Supplements sold as 'natural GLP-1' or 'nature's Ozempic' are not GLP-1 analogues. 'Natural GLP-1' supplements, such as berberine, are not medicines, are not regulated for this use and have no comparable trial evidence. They are available cheaply without assessment or clinical oversight, and dosing is not standardised. Treat dramatic weight-loss claims on these products with caution.

Orlistat is a licensed tablet that works differently: it blocks some dietary fat absorption and produces smaller average losses.¹ Nothing you eat reliably reproduces what a GLP-1 medicine does, though regular meals can support a reduced-calorie diet alongside treatment. For more on how the hormone behaves in the body, see our GLP-1 infographic, the GLP-1 statistics roundup, or the explainer on AMPK and GLP-1.

09 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹

10 · NHS access and switching

NHS access and switching between medicines

Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition, and the NHS primary-care rollout began in June 2025 with the highest-need groups first (initially BMI 40+ with four or more qualifying conditions).⁴⁶ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.

There is no licensed direct conversion between semaglutide and tirzepatide. Switching is done under prescriber supervision: typically the previous medicine is stopped, a washout interval observed, and Mounjaro started at a dose your prescriber judges appropriate, often the 2.5mg starting dose.¹